SOURCE

var number1=22;
var number2=33;
var mystring='aa';

var sum=number1+number2;
document.write(sum+"<br/>");

var sumstring=number1+mystring;
document.write(sumstring+"<br/>");

var stringnum=mystring+number2;
document.write(stringnum+"<br/>");

var stringNum=number1+"";

var stringNumSum=stringNumSum+"<br/>";
document.write(stringNumSum+"<br/>") ;
document.write("<br/>---------------<br/>");

var left=1;
var right=2;

left-=right;
document.write(left+"<br/>");

left+=right;
document.write(left+"<br/>");

left*=right;
document.write(left+"<br/>");

left/=right;
document .write(left+"<br/>");

document.write("<br/>---------------<br/>");

left=(1+2)+3;
right=(3+4)+1;

document.write((left>right)+" <br/>" )
document.write((left<right)+" <br/>" )
document.write((left>=right)+" <br/>" )
document.write((left<=right)+" <br/>" )
document.write((left==right)+" <br/>" )
document.write((left!=right)+" <br/>" )

document.write("<br/>---------------<br/>");

var logicOperataion=false;
logicOperation = (left>right)&&(left<right);
document.write(logicOperation+"<br/>");

logicOperation = true&&(left<right);
logicOperation = (left>right)||(left<right); 
document.write(logicOperation+"<br/>");
logicoperation = (left>right)||false;
document.write(logicOperation+"<br/>");
logicOperation =!(left>right);
document.write(logicoperation+"<br/>");
logicOperation =!(left<right);
document.write(logicoperation+"<br/>");

document.write("<br/>--------------<br/>");

document.write("Number('123' ):"+Number("123")+"<br/>");
document.write( "Number('3.1415'):"+Number("3.1415")+" <br/>");
document.write( "Number('hao123'):"+Number("hao123")+"<br/>");
document.write("Number('100px'):"+Number("100px")+"<br/>");

document.write("<br/>--------------<br/>");

document.write("parseInt('123'):"+ parseInt("123") +"<br/>");
document.write("parseInt('3.1415')"+parseInt("3.1415")+"<br/>");
document.write("parseInt('hao123')"+parseInt("hao123")+"<br/>");
document.write("parseInt('100px')"+parseInt("100px")+"<br/>");

document.write("<br/>--------------<br/>");

document.write("parseInt('+123'):"+ parseInt("+123")+ "<br/>");
document.write("parseInt('-123'):"+ parseInt("-123")+ "<br/>");

document.write("<br/>--------------<br/>");
var result=(2<1) ? "小芳" : "小红" ;
document.write(result);


document.write("<br/>--------------<br/>");
var number=1;
var stringNumber=1+"";
var stringNumber2=number.toString();
document.write(stringNumber+"<br/>")
document.write(stringNumber2+"<br/>");
//转义字符
document.write("<br/>--------------<br/>");
document.write("绿叶， <br/>初恋般的感觉~");
document.write("<br/>--------------<br/>");

document.write("绿叶，给你\'初恋\'般的感觉~"+"<br/>");
document.write("绿叶，给你\"初恋\"般的感觉~"+"<br/>");